ustreamer/src/libs/queue.c
2024-03-22 15:57:16 +02:00

113 lines
3.7 KiB
C

/*****************************************************************************
# #
# uStreamer - Lightweight and fast MJPEG-HTTP streamer. #
# #
# Copyright (C) 2018-2024 Maxim Devaev <mdevaev@gmail.com> #
# #
# This program is free software: you can redistribute it and/or modify #
# it under the terms of the GNU General Public License as published by #
# the Free Software Foundation, either version 3 of the License, or #
# (at your option) any later version. #
# #
# This program is distributed in the hope that it will be useful, #
# but WITHOUT ANY WARRANTY; without even the implied warranty of #
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the #
# GNU General Public License for more details. #
# #
# You should have received a copy of the GNU General Public License #
# along with this program. If not, see <https://www.gnu.org/licenses/>. #
# #
*****************************************************************************/
#include "queue.h"
#include <errno.h>
#include <time.h>
#include <assert.h>
#include <pthread.h>
#include "types.h"
#include "tools.h"
#include "threading.h"
us_queue_s *us_queue_init(uint capacity) {
us_queue_s *queue;
US_CALLOC(queue, 1);
US_CALLOC(queue->items, capacity);
queue->capacity = capacity;
US_MUTEX_INIT(queue->mutex);
pthread_condattr_t attrs;
assert(!pthread_condattr_init(&attrs));
assert(!pthread_condattr_setclock(&attrs, CLOCK_MONOTONIC));
assert(!pthread_cond_init(&queue->full_cond, &attrs));
assert(!pthread_cond_init(&queue->empty_cond, &attrs));
assert(!pthread_condattr_destroy(&attrs));
return queue;
}
void us_queue_destroy(us_queue_s *queue) {
US_COND_DESTROY(queue->empty_cond);
US_COND_DESTROY(queue->full_cond);
US_MUTEX_DESTROY(queue->mutex);
free(queue->items);
free(queue);
}
#define _WAIT_OR_UNLOCK(x_var, x_cond) { \
struct timespec m_ts; \
assert(!clock_gettime(CLOCK_MONOTONIC, &m_ts)); \
us_ld_to_timespec(us_timespec_to_ld(&m_ts) + timeout, &m_ts); \
while (x_var) { \
const int err = pthread_cond_timedwait(&(x_cond), &queue->mutex, &m_ts); \
if (err == ETIMEDOUT) { \
US_MUTEX_UNLOCK(queue->mutex); \
return -1; \
} \
assert(!err); \
} \
}
int us_queue_put(us_queue_s *queue, void *item, ldf timeout) {
US_MUTEX_LOCK(queue->mutex);
if (timeout == 0) {
if (queue->size == queue->capacity) {
US_MUTEX_UNLOCK(queue->mutex);
return -1;
}
} else {
_WAIT_OR_UNLOCK(queue->size == queue->capacity, queue->full_cond);
}
queue->items[queue->in] = item;
++queue->size;
++queue->in;
queue->in %= queue->capacity;
US_MUTEX_UNLOCK(queue->mutex);
US_COND_BROADCAST(queue->empty_cond);
return 0;
}
int us_queue_get(us_queue_s *queue, void **item, ldf timeout) {
US_MUTEX_LOCK(queue->mutex);
_WAIT_OR_UNLOCK(queue->size == 0, queue->empty_cond);
*item = queue->items[queue->out];
--queue->size;
++queue->out;
queue->out %= queue->capacity;
US_MUTEX_UNLOCK(queue->mutex);
US_COND_BROADCAST(queue->full_cond);
return 0;
}
#undef _WAIT_OR_UNLOCK
bool us_queue_is_empty(us_queue_s *queue) {
US_MUTEX_LOCK(queue->mutex);
const uint size = queue->size;
US_MUTEX_UNLOCK(queue->mutex);
return (bool)(queue->capacity - size);
}